Reinforcing bar for concrete structures



April 27, 1943.

GIG. GREULICH 2,317,454

REINFORCING BAR FOR CONCRETE STRUCTURES Filed July 15, 1940 Patented Apr. 27, 1943 REINFORCING BAR FOR CONCRETE S CTURES Gerald G. Greulich, Mount Lebanon, Pa.

Application July 15, 1940, Serial No. 345,637

1 Claim.

This invention relates to reinforcing bars and, more particularly, to those which are embedded in concrete and adapted to resist longitudinal movement therein and also the twisting action imposed thereby.

There are, in the prior art, instances wherein reinforcing bars for concrete structures are composed of sections which readily lend themselves to twisting and, when installed in the concrete in the twisted condition, serve to give the maximum resistance against longitudinal movement of the bar in the concrete when the bar is subiected to tension. An early form comprises two round sections which are twisted up together under tension: but this has not been successful because when subjected to compressive stresses in their length, they tend to separate. Another form comprises a single unitary structure embodyins two substantially round portions which are Joined by a web; and it is after this form that the device of the present invention has been designed.

It is an object of the present invention to provide an inexpensive reinforcing bar for concrete which will successfully resist all of the stresses imposed upon it.

Another object is the provision of a device of the class described which can be easily rolled on mills of existing design and cold-twisted after rolling.

The foregoing and other objects will become morehmhapparent after referring to the drawing, in w Figure 1 is a plan of the rolled section of the device of the invention prior to twisting;

Figure2is a crosssection; and

I 'igure3is avicwsimilartoligure ibutafter the rolled section has been twisted.

Referring more particularly to Figure 2, it will be observed that in section the reinforcing bar of the present invention comprises a twisted bar having'a somewhat flattened cross section such that the width thereof is approximately twice the height. That is to say, the dimension 1 is approximately twice the dimension u. The height. designated by the character a, is formed on either side of the mid-section of the reinforcing bar by substantially round or rod-shaped elements 2 and l, the width 0 of each of which shaped elements 2 and 3 are connected together by a portion 4 which is substantially rectangular in section, the width w thereof being substantially the same as the height u of the round or rod-shaped elements 2 and 3 and therefore approximately the same as either the height at or the width 12 of the latter. The thickness of the rectangular mid-section, designated at s, is approximately one-third the width 10 thereof, and accordingly approximately one-third of the height u of each of the round or rod-shaped portions 2 and 3. Such a cross section may be easily rolled, and when twisted takes the form illustrated in Figure 3. Thus there is provided two substantially round-sectioned iron bars connected by an integral intermediate portion which, when twisted up under tension, not only resists longitudinal movement in the concrete but withstands the untwisting action upon it by the latwr This relationship permits the use of a relatively thin web portion 4 as compared with the width thereof to permit easy twisting, but one which is at the same time sufllcient to prevent diiierential slipping under high bond stresses.

Referring to Figure 1, at spaced intervals and on alternate sides thereof, the portion 4 carries integral metallic protuberances which provide for increased rigidity.

While I have shown and described a specific embodiment of the present invention, it will be seenthatIdo notwishtobelimitedexactly thereto, since various modifications may be made without departing from the scope of the invention as defined in the appended claim.

I claim:

A reinforcing bar for concrete structures, comprising a twisted bar having a somewhat flattened cross section such that the width thereof is approximately twice the height, the mid-section of said bar being rectangular in cross-section and the remaining and adjoining portions being substantially oval and of a height which is approximately one-half the total width of said bar as a unit, the width of said mid-section being approximately the same as the height of said ad- Joining substantially oval portions, the thickness of said mid-section being approxima third the width thereof and alterna y onetuberances on opposite sides of the mid-portion 

